Wikipedia: Sound engineer
Wikibooks.org: Microphone Technique
Wikipedia: Horn Speaker
Com5.co.uk - Data Storage, Backup and Removable media solutions
Shure.com - Stage and studio microphones, wireless microphone systems, and mixers
Numark.com - Manufacturer of DJ accessories and audio equipment. Includes product catalogue and dealer locator.
Peavey.com - Peavey Electronics, manufacturer of musical equipment, gear, accessories and just about anything else you can think of. Rock on.
